Thumbnails generated from PDF in the "Media" section - how to show them in theme template?

Question

I have an ACF custom field for "File". It allows users to upload PDF files of some reports.

In the Media section in WP Admin, I can see that the PDF we upload auto-generates the thumbnails.

On the frontend, in my theme for the website, when I try to see the files array from the custom field, there's nothing related to the file that contains its thumbnail. Is there some way I can access the thumbnail for the PDF?

I know I can generate this myself using imagick or GD, but I'd like to leverage what WP has already done.

Answer 1

To get the attachment's icon, you can use wp_get_attachment_image().

For example, let's say I've uploaded a Word doc and it's got the ID 1234:

 // Parameter 3 - 'true' - tells WP to treat this as an icon.
 $img_tag = wp_get_attachment_image( 1234, 'thumbnail', true );
 // $img_tag contains:
 //   <img width="48" height="64"
 //        src="http://example.com/wp-includes/images/media/document.png"
 //        class="attachment-thumbnail size-thumbnail"
 //        alt="" loading="lazy"
 //   />